At startup time, mail will execute commands
in the system command file, /etc/mail.rc,
unless explicitly told not to by using the
-n option. Next, the commands in the user's
personal command file ~/.mailrc are
executed. mail then examines its command
line options to determine whether the user requested a new message to be sent
or existing messages in a mailbox to be examined.

To send a message to one or more people, mail
can be invoked with arguments which are the names of people to whom the mail
will be sent. You are then expected to type in your message, followed by a
control-D (‘^D’) at the beginning of a line. The section below,
Replying to
or originating mail, describes some features of
mail available to help you compose your
letter.

In normal usage, mail is given no arguments
and checks your mail out of the post office, then prints out a one line header
of each message found. The current message is initially set to the first
message (numbered 1) and can be printed using the
print command (which can be abbreviated
p). Moving among the messages is much like
moving between lines in ed(1); you
may use + and
- to shift forwards and backwards, or
simply enter a message number to move directly.

After examining a message you can delete
(d) or
reply
(r) to it. Deletion causes the
mail program to forget about the message.
This is not irreversible; the message can be
undeleted
(u) by giving its number, or the
mail session can be aborted by giving the
exit (x)
command. Deleted messages, however, will usually disappear, never to be seen
again.

Commands such as print and
delete can be given a list of message
numbers as arguments to apply to a number of messages at once. Thus
delete 1 2 deletes messages 1 and 2, while
delete 1-5 deletes messages 1 through 5.

Messages may also be selected using one of the following categories:

*

all messages

$

last message

:d

deleted messages

:n

new messages

:o

old messages

:r

read messages

:u

unread messages

Thus the command top, which prints the first
few lines of a message, could be used in top
* to print the first few lines of all messages.

You can use the reply command to set up a
response to a message, sending it back to the person who it was from. Text you
then type in, up to an end-of-file, defines the contents of the message. While
you are composing a message, mail treats
lines beginning with the tilde (‘~’) character specially. For
instance, typing ~m (alone on a line) will
place a copy of the current message into the response, right shifting it by a
single tab-stop (see the indentprefix
variable, below). Other escapes will set up subject fields, add and delete
recipients to the message, and allow you to escape to an editor to revise the
message or to a shell to run some commands. (These options are given in the
summary below.)

You can end a mail session with the
quit (q)
command. Messages which have been examined go to your
mbox file unless they have been deleted, in
which case they are discarded. Unexamined messages go back to the post office
(see the -f option above).

It is also possible to create personal distribution lists so that, for instance,
you can send mail to “cohorts” and have
it go to a group of people. Such lists can be defined by placing a line like

alias cohorts bill ozalp jkf mark
kridle@ucbcory

in the file .mailrc in your home directory.
The current list of such aliases can be displayed with the
alias command in
mail. System wide distribution lists can be
created by editing /etc/mail/aliases (see
aliases(5)); these are kept in
a different syntax. In mail you send, personal aliases will be expanded in
mail sent to others so that they will be able to
reply to the recipients. System wide
aliases are not expanded when the mail is sent, but any reply returned to the
machine will have the system wide alias expanded as all mail goes through an
MTA.

Each command is typed on a line by itself, and may take arguments following the
command word. The command need not be typed in its entirety — the first
command which matches the typed prefix is used. For commands which take
message lists as arguments, if no message list is given, then the next message
forward which satisfies the command's requirements is used. If there are no
messages forward of the current message, the search proceeds backwards, and if
there are no good messages at all, mail
types “No applicable messages” and aborts the command.

(alt) The
alternates command is useful if you
have accounts on several machines. It can be used to inform
mail that the listed addresses are
really you. When you reply to messages,
mail will not send a copy of the
message to any of the addresses listed on the
alternates list. If the
alternates command is given with no
argument, the current set of alternate names is displayed.

(fo) The
folder command switches to a new mail
file or folder. With no arguments, it tells you which file you are
currently reading. If you give it an argument, it will write out changes
(such as deletions) you have made in the current file and read in the new
file. Some special conventions are recognized for the name. # means the
previous file, % means your system mailbox, %user means user's system
mailbox, & means your mbox file, and
+folder means a file in your folder directory.

Add the list of header fields named to the
ignored list. Header fields in the ignore
list are not printed on your terminal when you print a message. This
command is very handy for suppression of certain machine-generated header
fields. The Type and
Print commands can be used to print a
message in its entirety, including ignored fields. If
ignore is executed with no arguments,
it lists the current set of ignored fields.

Incorporate any new messages that have arrived while mail is being read.
The new messages are added to the end of the message list, and the current
message is reset to be the first new mail message. This does not renumber
the existing message list, nor does it cause any changes made so far to be
saved.

(q) Terminates the session, saving all
undeleted, unsaved messages in the user's
mbox file in his login directory,
preserving all messages marked with
hold or
preserve or never referenced in his
system mailbox, and removing all other messages from his system mailbox.
If new mail has arrived during the session, the message
“You have new mail” is given. If
given while editing a mailbox file with the
-f flag, then the edit file is
rewritten. A return to the shell is effected, unless the rewrite of edit
file fails, in which case the user can escape with the
exit command.

Add the list of header fields named to the
retained list. Only the header fields in
the retain list are shown on your terminal when you print a message. All
other header fields are suppressed. The
Type and
Print commands can be used to print a
message in its entirety. If retain is
executed with no arguments, it lists the current set of retained
fields.

(s) Takes a message list and a filename
and appends each message in turn to the end of the file. The filename in
quotes, followed by the line count and character count is echoed on the
user's terminal.

saveretain
is to save what
retain is to
print and
type. Header fields thus marked are the
only ones saved with a message when saving by
save or when automatically saving to
mbox.
saveretain overrides
saveignore.

(se) With no arguments, prints all
variable values. Otherwise, sets option. Arguments are of the form
option=value (no space before or after =)
or option. Quotation marks may be placed
around any part of the assignment statement to quote blanks or tabs, i.e.,
set
indentprefix="->".

mail presents message headers in
windowfuls as described under the
headers command. You can move
mail's attention forward to the next
window with the z command. Also, you
can move to the previous window by using
z-.

Here is a summary of the tilde escapes, which are used when composing messages
to perform special functions. Tilde escapes are only recognized at the
beginning of lines. The name “tilde escape” is somewhat of a
misnomer since the actual escape character can be set by the option
escape.

Read the named messages into the message being sent. If no messages are
specified, read in the current message. Message headers currently being
ignored (by the ignore or
retain command) are not included.

Read the named messages into the message being sent, indented by a tab or
by the value of indentprefix. If no
messages are specified, read the current message. Message headers
currently being ignored (by the ignore
or retain command) are not included.

Invoke an alternate editor (defined by the
VISUAL option) on the message collected
so far. Usually, the alternate editor will be a screen editor. After you
quit the editor, you may resume appending text to the end of your message.

Pipe the message through the command as a filter. If the command gives no
output or terminates abnormally, retain the original text of the message.
The command fmt(1) is often
used as command to rejustify the
message.

A number of options can be set in the .mailrc
file to alter the behavior of mail,
controlled via the set and
unset commands. Options may be either
binary, in which case it is only significant to see whether they are set or
not; or string, in which case the actual value is of interest. The binary
options include the following:

append

Causes messages saved in mbox to be
appended to the end rather than prepended. This should always be set
(perhaps in /etc/mail.rc).

ask,
asksub

Causes mail to prompt you for the
subject of each message you send. If you respond with simply a newline, no
subject field will be sent.

askbcc

Causes you to be prompted for additional blind carbon copy recipients at
the end of each message. Responding with a newline indicates your
satisfaction with the current list.

askcc

Causes you to be prompted for additional carbon copy recipients at the end
of each message. Responding with a newline indicates your satisfaction
with the current list.

autoinc

Causes new mail to be automatically incorporated when it arrives. Setting
this is similar to issuing the inc
command at each prompt, except that the current message is not reset when
new mail arrives.

autoprint

Causes the delete command to behave
like dp; thus, after deleting a
message, the next one will be typed automatically.

debug

Setting the binary option debug is the
same as specifying -d on the command
line and causes mail to output all
sorts of information useful for debugging
mail.

dot

The binary option dot causes
mail to interpret a period alone on a
line as the terminator of a message you are sending.

Causes mail to use the specified sender
address in the “From:” field of the message header. A
stripped down version of the address is also used in the message envelope.
If unset, the message will not include an explicit sender address and a
default value will be added by the MTA, typically
“user@host”. This value can be overridden by specifying the
-r flag on the command line.

hold

This option is used to hold messages in the system mailbox by
default.

ignore

Causes interrupt signals from your terminal to be ignored and echoed as
@'s.

ignoreeof

An option related to dot is
ignoreeof which makes
mail refuse to accept a control-D as
the end of a message. ignoreeof also
applies to mail command mode.

keep

Setting this option causes mail to
truncate your system mailbox instead of deleting it when it's empty.

keepsave

Messages saved with the save command
are not normally saved in mbox at quit
time. Use this option to retain those messages.

metoo

Usually, when a group is expanded that contains the sender, the sender is
removed from the expansion. Setting this option causes the sender to be
included in the group.

noheader

Setting the option noheader is the same
as giving the -N flag on the command
line.

nosave

Normally, when you abort a message with two interrupt characters (usually
control-C), mail copies the partial
letter to the file dead.letter in your
home directory. Setting the binary option
nosave prevents this.

quiet

Suppresses the printing of the version when first invoked.

Replyall

Reverses the sense of reply and
Reply commands.

searchheaders

If this option is set, then a message-list specifier in the form
“/x:y” will expand to all messages containing the substring
‘y’ in the header field ‘x’. The string search
is case insensitive. If ‘x’ is omitted, it will default to
the “Subject” header field. The form “/to:y”
is a special case, and will expand to all messages containing the
substring ‘y’ in the “To”, “Cc”
or “Bcc” header fields. The check for “to” is
case sensitive, so that “/To:y” can be used to limit the
search for ‘y’ to just the “To:” field.

skipempty

Don't send messages with an empty body.

verbose

Setting the option verbose is the same as
using the -v flag on the command line.
When mail runs in verbose mode, the
actual delivery of messages is displayed on the user's terminal.

Pathname of the text editor to use in the
visual command and
~v escape. If not defined,
/usr/bin/vi is used.

crt

The valued option crt is used as a
threshold to determine how long a message must be before
PAGER is used to read it. If
crt is set without a value, then the
height of the terminal screen stored in the system is used to compute the
threshold (see stty(1)).

escape

If defined, the first character of this option gives the character to use
in the place of ~ to denote escapes.

folder

The name of the directory to use for storing folders of messages. If this
name begins with a ‘/’,
mail considers it to be an absolute
pathname; otherwise, the folder directory is found relative to your home
directory.

indentprefix

String used by the ~m tilde escape for
indenting messages, in place of the normal tab character
(‘^I’). Be sure to quote the value if it contains spaces or
tabs.

record

If defined, gives the pathname of the file used to record all outgoing
mail. If not defined, then outgoing mail is not so saved.

screen

Size of window of message headers for
z.

sendmail

Pathname to an alternative mail delivery system.

toplines

If defined, gives the number of lines of a message to be printed out with
the top command; normally, the first
five lines are printed.